Nonneurologic morbidity and profound hypothermia in aortic surgery

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

Neuroprotection during Open Aortic Arch Surgery: Cerebral Perfusion Methods and Temperature

Neuroprotection is important in open aortic arch surgery because of the dependence of brain tissues on cerebral perfusion. Therefore, several techniques have been developed to reduce cerebral ischemia and improve outcomes in open aortic arch surgery. In this review, I describe various neuroprotective strategies, such as profound and deep hypothermic circulatory arrest, selective antegrade cerebral perfusion, retrograde cerebral perfusion, and lower body circulatory arrest; compare their advantages and disadvantages, and discuss their evolution and current status by reviewing relevant literature.

Prevention and management of difficult hemostasis in acute type A aortic dissection repair

Postoperative bleeding after surgery for acute aortic dissection is one of the most common complications and has an important influence on mortality and morbidity. Therefore, various methods have been introduced to prevent or manage postoperative bleeding. In this article, we investigated the causes of bleeding after surgery for acute aortic dissection, and introduce appropriate transfusion or pharmacologic treatment, topical hemostatic agents, and local compressive maneuver to manage it.

Recombinant Activated Factor VII in Aortic Surgery for Patients Under Hypothermic Circulatory Arrest

Purpose

We aimed to identify the risk factors of critical bleeding and investigate the safety of recombinant activated factor VII (rFVIIa) in aortic surgery under hypothermic circulatory arrest (HCA).

Patients and Methods

The present single-center retrospective study compared the baseline characteristics of 144 patients who underwent aortic surgery under HCA at our institute. Among the total cohort of 144 patients, 42 received rFVIIa (rFVIIa group), while the remaining 102 patients did not (non-rFVIIa group). Perioperative bleeding and transfusions, postoperative 30-day mortality, and adverse events (AEs) were analyzed in 29 propensity score-matched pairs.

Results

Before surgery, the rFVIIa group demonstrated a greater number of shocks (p=0.019), higher JapanSCORE II mortality rate (p=0.033), low platelet count (p=0.015) and fibrinogen (p<0.001) level, prolonged activated partial thromboplastin time (aPTT) (p=0.005) and prothrombin time international normalized ratio (PT-INR) (p=0.006), and longer aortic cross clamp time (p=0.049). Postoperative bleeding, transfusion, 30-day mortality, and AEs were comparable between the groups both in the entire-unmatched cohort and propensity score matching cohort.

Conclusion

Preoperative shock, higher JapanSCORE II mortality rates, low platelet and fibrinogen levels, prolonged aPTT and PT-INR, and longer aortic clamping time might be risk factors for excessive bleeding and indicate the need for rFVIIa treatment. The present study suggests that rFVIIa can be safely used to address critical and continuous bleeding in spite of adequate transfusion and supplementation of other coagulation factors in aortic surgery under HCA, without an increase in 30-day mortality and AEs.

Association between Duration of Deep Hypothermic Circulatory Arrest and Surgical Outcome in Patients with Acute Type A Aortic Dissection: A Large Retrospective Cohort Study

(1) Background: Deep hypothermic circulatory arrest (DHCA) with selective antegrade cerebral perfusion (ACP) is an established cerebral protection technique for the conduction of complex surgical procedures involving the aortic arch. It is controversial whether the duration of DHCA is associated with adverse outcome in patients with acute type A aortic dissection (AAAD). Our goal was to investigate whether DHCA time was associated with surgical outcome in patients undergoing a surgical treatment of AAAD. (2) Methods: A total of 410 patients were divided into two groups based on the DHCA time less than 60 min and equal to or longer than 60 min. (3) Results: Patients with longer DHCA times were significantly younger (p = 0.001). Intraoperatively, complex procedures with aortic arch surgery were more common in patients with longer DHCA times (p < 0.001). Accordingly, cardiopulmonary bypass (p < 0.001), cross-clamping (p < 0.001) and DHCA times (p < 0.001) were significantly longer in this group. Postoperatively, only the duration of mechanical ventilation (p < 0.001) and the rate of tracheotomy were significantly higher in these patients. Thirty-day mortality was satisfactory for both groups (p = 0.746). (4) Conclusions: Our results showed that improvements in perioperative management including ACP allow for the successful performance of surgical treatment of AAAD under DHCA with a duration of even longer than 60 min.

Spinal cord injury during selective cerebral perfusion and segmental artery occlusion: an experimental study

OBJECTIVES

Since selective cerebral perfusion (SCP) has been used in aortic arch surgical procedures, the core temperature during lower body circulatory arrest (LBCA) has been steadily rising. Simultaneously, the use of a frozen elephant trunk (FET) graft has been increasing. The safe period of LBCA in relation to spinal cord ischaemic tolerance in combination with segmental artery occlusion by the FET procedure has not been defined.

METHODS

Sixteen pigs were assigned to undergo 65 (n = 10) or 90 min (n = 6) of SCP at 28°C with LBCA in combination with occlusion of the 8 uppermost segmental arteries in the thoracic (Th) aorta (15-20 cm FET, Th8-level). The follow-up period consisted of a 6-h intensive period and a 5-day observation period. Near-infrared spectroscopy of the collateral network was used to determine spinal cord oxygenation. The neurological status of the patients was evaluated daily, and the brain and the spinal cord were harvested for a histopathological analysis.

RESULTS

Five out of 6 pigs after 90 min and 1 out of 10 pigs after 65 min of LBCA died within 48 h of multiorgan failure. Of the survivors in the 65-min group, 6 out of 9 had paraparesis/paraplegia; the remaining 3 reached normal function. The lone survivor after 90 min of LBCA was paraplegic. Nadir near-infrared spectroscopy of the collateral network values at Th8 and Th10 were 34 (±5) and 39 (±4), and they were reached within 35 min of SCP in both groups.

CONCLUSIONS

An extended FET graft with LBCA and SCP durations >65 min at 28°C results in a poor outcome.

Moderate hypothermia with remote ischaemic preconditioning improves cerebral protection compared to deep hypothermia: a study using a surviving porcine model

OBJECTIVES

The optimal temperature management of hypothermic circulatory arrest is still controversial. Moderate hypothermia preserves cerebral autoregulation and shortens cardiopulmonary bypass (CPB) duration. However, moderate hypothermia alone has inferior organ protection to deep hypothermia, so adjuncts that increase the ischaemic tolerance are needed. Thus, we hypothesized that a combination of remote ischaemic preconditioning (RIPC) and moderate hypothermia would be superior to deep hypothermia alone.

METHODS

Sixteen pigs were randomized to either RIPC or control groups (8 + 8). The RIPC group underwent 4 cycles of transient hind limb ischaemia. The RIPC group underwent cooling with CPB to 24°C, and the control group underwent cooling with CPB to 18°C, followed by a 30-min arrest period and subsequent rewarming to 36°C. Measurements of cerebral metabolism were made from sagittal sinus blood samples and common carotid artery blood flow. The permissible periods of hypothermic circulatory arrest were calculated based on these measurements. Neurological recovery was evaluated daily during a 7-day follow-up, and the brain was harvested for histopathological analysis.

RESULTS

Six pigs in the RIPC group reached normal neurological function, but none in the control group reached normal neurological function (P = 0.007). The composite neurological score of all postoperative days was higher in the RIPC group than in the control group [55 (52-58) vs 45 (39-51), P = 0.026]. At 24°C, the estimated permissible periods of hypothermic circulatory arrest were 21 (17-25) min in the RIPC group and 11 (9-13) min in the control group (P = 0.007).

CONCLUSIONS

RIPC combined with moderate hypothermia provides superior cerebral protection.

Hybrid repair versus conventional open repair for thoracic aortic arch aneurysms

BACKGROUND

Thoracic aortic arch aneurysms (TAAs) can be a life-threatening condition due to the potential risk of rupture. Treatment is recommended when the risk of rupture is greater than the risk of surgical complications. Depending on the cause, size and growth rate of the TAA, treatment may vary from close observation to emergency surgery. Aneurysms of the thoracic aorta can be managed by a number of surgical techniques. Open surgical repair (OSR) of aneurysms involves either partial or total replacement of the aorta, which is dependent on the extent of the diseased segment of the aorta. During OSR, the aneurysm is replaced with a synthetic graft. Hybrid repair (HR) involves a combination of open surgery with endovascular aortic stent graft placement. Hybrid repair requires varying degrees of invasiveness, depending on the number of supra-aortic branches that require debranching. The hybrid technique that combines supra-aortic vascular debranching with stent grafting of the aortic arch has been introduced as a therapeutic alternative. However, the short- and long-term outcomes of HR remain unclear, due to technical difficulties and complications as a result of the angulation of the aortic arch as well as handling of the arch during surgery.

OBJECTIVES

To assess the effectiveness and safety of HR versus conventional OSR for the treatment of TAAs.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 March 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations.

SELECTION CRITERIA

We considered for inclusion in the review all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing HR to OSR for TAAs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all titles and abstracts obtained from the literature search to identify those that met the inclusion criteria. We retrieved the full text of studies deemed as potentially relevant by at least one review author. The same review authors screened the full-text articles independently for inclusion or exclusion.

MAIN RESULTS

No RCTs or CCTs met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of HR compared to OSR in people with TAAs, and we are unable to provide high-certainty evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs are necessary, addressing the objective of this review.

Level of serum soluble lumican and risks of perioperative complications in patients receiving aortic surgery

Objective

Several serum biomarkers have been investigated for their potential as diagnostic tools in aortic disease; however, no study has investigated the association between serum biomarkers and outcomes after aortic surgery. This study explored the predictive ability of serum soluble lumican in postoperative outcomes after aortic surgery.

Methods

In total, 58 patients receiving aortic surgery for aortic dissection or aneurysm at Linkou Chang Gung Memorial Hospital in Taiwan in December 2011–September 2018 were enrolled. Blood samples were collected immediately upon patients’ arrival in the intensive care unit after aortic surgery. The diagnostic properties of soluble lumican levels were assessed by performing receiver operating characteristic (ROC) curve analysis. The confidence interval (CI) of the area under the ROC curve (AUC) was measured using DeLong’s nonparametric method and the optimal cutoff was determined using the Youden index.

Results

The serum soluble lumican level distinguished prolonged ventilation (AUC, 73.5%; 95% CI, 57.7%–89.3%) and hospital stay for >30 days (AUC, 78.2%; 95% CI, 61.6%–94.7%). The optimal cutoffs of prolonged ventilation and hospital stay for >30 days were 1.547 and 5.992 ng/mL, respectively. The sensitivity and specificity were respectively 100% (95% CI, 71.5%–100%) and 40.4% (95% CI, 26.4%–55.7%) for prolonged ventilation and 58% (95% 27.7%–84.8%) and 91.3% (95% CI, 79.2%–97.6%) for hospital stay for >30 days.

Conclusions

The serum soluble lumican level can be a potential prognostic factor for predicting poor postoperative outcomes after aortic surgery. However, more studies are warranted in the future.

Different hypothermic and cerebral perfusion strategies in extended arch replacement for acute type a aortic dissection: a retrospective comparative study

BACKGROUND

The optimal hypothermic level in total arch replacement with stented elephant trunk implantation for acute type A aortic dissection (aTAAD) has not been established, and the superiority of unilateral or bilateral cerebral perfusion remains a controversial issue. Therefore, we evaluated the application of moderate hypothermic circulatory arrest (MHCA) with a core temperature of 29 °C and bilateral selective antegrade cerebral perfusion in aTAAD treated by total arch replacement with stented elephant trunk implantation.

METHODS

From July 2019 to January 2020, 25 aTAAD patients underwent total arch replacement with stented elephant trunk implantation via MHCA (29 °C) and bilateral selective antegrade cerebral perfusion (modified group). Thirty-six patients treated by the same procedure with MHCA (25 °C) and unilateral selective antegrade cerebral perfusion during this period were selected as controls.

RESULTS

There were no differences between the two groups of patients in terms of age, sex, incidence of hypertension, malperfusion, and pericardial effusion, although the incidence of cardiac tamponade was higher in the modified group (control 2.8%, modified 20%; P = 0.038). The lowest mean circulatory arrest temperature was 24.6 ± 0.9 °C in the control group, and 29 ± 0.8 °C in the modified group (P <  0.001). In-hospital mortality was 4.9% (3/61) for the entire cohort (control 8.3%, modified 0; P = 0.262). The incidence of permanent neurologic deficit was 4.9% (control 8.3%, modified 0; P = 0.262). There were no significant differences in the occurrence of temporary neurological deficit, renal failure, and paraplegia between groups. The rate of major adverse events in the modified group was lower (30.6% vs. 4%, P = 0.019). A shorter duration of ventilation and ICU stay was identified in the modified group, as well as a reduced volume of drainage within the first 48 h and red blood cell transfusion.

CONCLUSIONS

The early results of MHCA (29 °C) and bilateral selective antegrade cerebral perfusion applied in total arch replacement with stented elephant trunk implantation for aTAAD were acceptable, providing similar inferior cerebral and visceral protection compared with that of the conventional strategy. A higher core temperature may account for the shorter duration of ventilation and ICU stay, as well as a reduced volume of drainage and red blood cell transfusion.

Hypothermic circulatory arrest induced coagulopathy: rotational thromboelastometry analysis

Objectives

Hypothermic circulatory arrest (HCA) has been considered to cause coagulopathy during cardiac surgery. However, coagulopathy associated with HCA has not been understood clearly in details. The objective of this study is to analyze the details of coagulopathy related to HCA in cardiac surgery by using rotational thromboelastometry (ROTEM).

Methods

We retrospectively analyzed 38 patients who underwent elective cardiac surgery (HCA group = 12, non-HCA group = 26) in our hospital. Blood samples were collected before and after cardiopulmonary bypass (CPB). Standard laboratory tests (SLTs) and ROTEM were performed. We performed four ROTEM assays (EXTEM, INTEM, HEPTEM and FIBTEM) and analyzed the following ROTEM parameters: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF) and maximum clot elasticity (MCE). The amount of perioperative bleeding, intraoperative transfusion and perioperative data were compared between the HCA and non-HCA group.

Results

Operation time and hemostatic time were significantly longer in the HCA group, whereas CPB time had no difference between the groups. The amount of perioperative bleeding and intraoperative transfusion were much higher in the HCA group. SLTs showed no difference between the groups both after anesthesia induction and after protamine reversal. In ROTEM analysis, MCE contributed by platelet was reduced in the HCA group, whereas MCE contributed by fibrinogen had no difference.

Conclusion

Our study confirmed that the amount of perioperative bleeding and intraoperative transfusion were significantly higher in the HCA group. ROTEM analysis would indicate that clot firmness contributed by platelet component is reduced by HCA in cardiac surgery.

Engineering Human Stasis for Long-Duration Spaceflight

Suspended animation for deep-space travelers is moving out of the realm of science fiction. Two approaches are considered: the first elaborates the current medical practice of therapeutic hypothermia; the second invokes the cascade of metabolic processes naturally employed by hibernators. We explore the basis and evidence behind each approach and argue that mimicry of natural hibernation will be critical to overcome the innate limitations of human physiology for long-duration space travel.

Abdominal organ protection strategy for aortic arch aneurysm surgery

INTRODUCTION

Body temperature maintained during open distal anastomosis in patients who undergo aortic surgery has been showing an upward trend; however, a higher temperature may increase visceral organ and spinal cord injury. Distal perfusion may reduce abdominal organ injury, especially acute kidney injury (AKI).

METHODS

From 2009 to 2016, 56 patients who underwent ascending aortic and/or aortic arch surgery were enrolled. Open distal anastomosis was performed using one of three protection strategies: 1) systemic temperature of 25°C followed by selective cerebral perfusion (SCP) with lower body circulatory arrest (Group CA25, n=27); 2) systemic temperature of 28°C followed by SCP with lower body circulatory arrest (Group CA28, n=4); and 3) systemic temperature of 28°C followed by SCP with distal aortic perfusion (Group DP, n=25).

RESULTS

During the postoperative course, levels of blood urea nitrogen, creatinine, liver enzymes, lactate dehydrogenase and lactate in Groups CA28 and CA25 were significantly higher than those in Group DP. AKI defined by the AKI Network occurred in 28 cases (50%) and 3 cases required permanent hemodialysis. AKI was significantly higher in Groups CA25 and CA28 than in Group DP (p=0.026). Mid-term follow-up showed that patients who developed postoperative AKI were more likely to suffer from cardiovascular events.

CONCLUSIONS

Distal perfusion during open distal anastomosis reduced kidney and liver injury after thoracic aortic surgery despite an increased body temperature of up to 28°C. This strategy may be useful to prevent AKI, liver dysfunction, the need for hemodialysis and multiple organ failure and could improve mid-term results.

Aortic Surgery and Deep-Hypothermic Circulatory Arrest: Anesthetic Update

Aortic arch surgery has become increasingly complex, and novel surgical approaches have been utilized. Efforts aimed at improving neurological outcomes in this patient population have been numerous, with varying degrees of success. This article summarizes the anesthetic considerations for procedures on the aortic arch, including evidence-based outcomes with respect to temperature management, perfusion strategies, hemodynamic goals, adjunct agents, and neuromonitoring.

Deep Hypothermia and Circulatory Arrest in Adults

Brain protection during cardiopulmonary bypass has been the subject of intense research. Deep hypothermic circulatory arrest (DHCA) continues to be used for that goal during complex aortic arch and large intracranial aneurysm surgeries. The anesthetic management for adult patients undergoing these types of procedures requires specific knowledge and expertise. Based on our experience and review of the current literature, the authors highlight the key areas of the anesthetic plan, discussing the risk factors associated with adverse neurologic outcome as well as the rationale for decisions regarding specific monitors and medications. In the conclusion an anesthetic protocol for adult patients undergoing DHCA is suggested.

Optimal temperature management in aortic arch operations

Hypothermic circulatory arrest is a critical component of aortic arch procedures, without which these operations could not be safely performed. Despite the use of hypothermia as a protective adjunct for organ preservation, aortic arch surgery remains complex and is associated with numerous complications despite years of surgical advancement. Deep hypothermic circulatory arrest affords the surgeon a safe period of time to perform the arch reconstruction, but this interruption of perfusion comes at a high clinical cost: stroke, paraplegia, and organ dysfunction are all potential-associated complications. Retrograde cerebral perfusion was subsequently developed as a technique to improve upon the rates of neurologic dysfunction, but was done with only modest success. Selective antegrade cerebral perfusion, on the other hand, has consistently been shown to be an effective form of cerebral protection over deep hypothermia alone, even during extended periods of circulatory arrest. A primary disadvantage of using deep hypothermic circulatory arrest is the prolonged bypass times required for cooling and rewarming which adds significantly to the morbidity associated with these procedures, especially coagulopathic bleeding and organ dysfunction. In an effort to mitigate this problem, the degree of hypothermia at the time of the initial circulatory arrest has more recently been reduced in multiple centers across the globe. This technique of moderate hypothermic circulatory arrest in combination with adjunctive brain perfusion techniques has been shown to be safe when performing aortic arch operations. In this review, we will discuss the evolution of these protection strategies as well as their relative strengths and weaknesses.

Aggressive re-warming at 38.5 °C following deep hypothermia at 21 °C increases neutrophil membrane bound elastase activity and pro-inflammatory factor release

Background

Cardiopulmonary bypass (CPB) is often performed under hypothermic condition. The effects of hypothermia and re-warming on neutrophil activity are unclear. This study aimed to compare the effects of different hypothermia and re-warming regimens on neutrophil membrane bound elastase (MBE) activity and the release of pro-inflammatory factors from neutrophils.

Methods

Human neutrophils were exposed to different hypothermia and re-warming regimens. MBE activity and the release of interleukin (IL)-β1, IL-6, IL-8, and tumor necrosis factor (TNF)-α were measured.

Results

Neutrophil MBE activity was significantly reduced after 60-min moderate (28 °C) or deep (21 °C) hypothermic treatment. Compared with normothermic (37 °C) re-warming, aggressive re-warming (38.5°) for 120 min following deep hypothermia (21 °C) dramatically increased neutrophil MBE activity (P < 0.05). Co-incubation of neutrophils with platelet-rich plasma further increased MBE activity significantly under all the tested temperature regimens. IL-β1 release from neutrophils was significantly higher after deep hypothermia (21 °C) followed by normothermic (37 °C) re-warming than after moderate hypothermia (28 °C) followed by normothermic re-warming (P < 0.05). Aggressive re-warming (38.5°) following deep hypothermia significantly increased the release of IL-β1, IL-8, and TNF-α from neutrophil compared with moderate re-warming (37 °C) (all P < 0.05).

Conclusion

Aggressive re-warming following deep hypothermia may contribute to CPB-associated tissue injury by increasing neutrophil MBE activity and stimulating pro-inflammatory factor release, thus, should be avoided. The optimal hypothermic temperature of CPB should be determined based on patient clinical characteristics and surgery type.

Moderate hypothermic circulatory arrest in total arch repair for acute type A aortic dissection: clinical safety and efficacy

BACKGROUND

Continued debates exist regarding the optimal temperature during hypothermic circulatory arrest (HCA) in aortic arch repair for patients with type A aortic dissection (TAAD). This study seeks to examine whether the use of moderate HCA in emergency aortic arch surgery provides comparable operative outcomes to deep HCA for patients with acute TAAD.

METHODS

We prospectively enrolled 74 consecutive patients (mean age 47.7±9.8 years, 54 males) with acute TAAD, who underwent emergency total arch replacement and frozen elephant trunk implantation under HCA (18-28 °C) with unilateral selective antegrade cerebral perfusion (uSACP). Patients were divided into two groups based on the nasopharyngeal temperature at the initiation of HCA: deep HCA (DHCA, <20 °C) in 35 (47.3%) and moderate HCA (MHCA, 20-28 °C) in 39 (52.7%). Operative outcomes including mortality, morbidity and visceral organ functions were compared between the two groups.

RESULTS

The mean times of cardiopulmonary bypass (CPB) and aortic cross-clamp were 211±54 and 238±62 minutes (P=0.053) and 118±27 and 142±45 minutes (P=0.005) in the MHCA and DHCA groups, respectively. Operative mortality did not differ between two groups (10.2% in MHCA vs. 14.3% in DHCA groups, P=0.862). Nor did the incidence of morbidities differ between the two groups (P>0.05). The temporal trend in the changes of postoperative levels of creatinine, aspartate aminotransferase, total bilirubin and lactate did not differ between two groups (P>0.05). Multivariate analysis found that the temperature during HCA (MHCA vs. DHCA) did not affect operative mortality, morbidities and neurologic complications. Instead, CPB time (in minutes) was the risk factor for operative mortality (odds ratio, 1.032; 95% confidence interval, 1.004-1.061; P=0.023).

CONCLUSIONS

Moderate HCA is associated with equivalent operative mortality and morbidity and visceral organ functions compared to deep HCA in patients with acute TAAD undergoing total arch replacement under uSACP. This study implies the clinical safety and efficacy of moderate HCA in emergency aortic arch repair for such patients, which provides equivalent cerebral and visceral organ protection while decreasing CPB and cross-clamp times without increasing the risk of operative mortality and morbidity.

How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data.

"Open" approach to aortic arch aneurysm repair

Aortic arch aneurysm is a relatively rare entity in cardiac surgery. Repair of such aneurysms, either in isolation or combined with other cardiac procedures, remains a challenging task. The need to produce a relatively bloodless surgical field with circulatory arrest, while at the same time protecting the brain, is the hallmark of this challenge. However, a clear understanding of the topic allows a better and less morbid approach to such a complex surgery. Literature has shown the advantage of selective cerebral perfusion techniques in comparison with only circulatory arrest. Ability to perfuse the brain has allowed circulatory arrest temperatures at moderate hypothermia without the need for deep hypothermia. Even though cannulation site selection appears to be a minor issue, literature has shown that the subclavian/axillary route has the best outcomes and that femoral cannulation should only be reserved for no access patients. Although different techniques for arch anastomosis have been described, we routinely perform the distal first technique as we find it to be less cumbersome and easiest to reproduce. In this review our aim is to outline a systematic approach to aortic arch surgery. Starting with indications for intervention and proceeding with approaches on site of cannulation, approaches to brain protection with hypothermia and selective cerebral perfusion and finally surgical steps in performing the distal and arch vessels anastomosis.

Consensus on hypothermia in aortic arch surgery

Considered a standard part of aortic arch surgery, hypothermia can sufficiently reduce cerebral metabolic demand to permit reasonable periods of circulatory arrest. Yet despite its ubiquitous application and critical importance, temperature classification in hypothermic circulatory arrest is still without clear definition. The following Consensus from experts in high-volume aortic institutions defines 'profound', 'deep', 'moderate', and 'mild' hypothermia and recommends standardized monitoring sites, so as to facilitate more consistent reporting and robust analysis.

Modern temperature management in aortic arch surgery: the dilemma of moderate hypothermia

Arch surgery is undoubtedly among the most technically and strategically challenging endeavours in aortic surgery, requiring thorough understanding not only of cardiovascular physiology, but also in particular, of neurophysiology (cerebral and spinal cord), and is still associated with significant mortality and morbidity. In the late 1980s, when deep hypothermic circulatory arrest (HCA) had gained widespread acceptance as the standard approach for arch surgery, antegrade selective cerebral perfusion (SCP), as an adjunct to deep HCA, began its triumphal march, offering excellent neuroprotection and improved overall outcome. This encouraged the use of antegrade SCP in combination with steadily increasing body core temperatures--a trend culminating in the progressive advocation of moderate-to-mild temperatures up to 35 °C, and even normothermia. The impetus for progressive temperature elevation was the limitation of adverse effects of profound hypothermia and the most welcome side effect of significantly shorter cooling and rewarming periods on cardiopulmonary bypass (CPB), and thereby, potentially, the alleviation of the systemic inflammatory response and, in particular, the risk of severe postoperative bleeding (and other organ dysfunctions). The safe limits of prolonged distal circulatory arrest, particularly with regard to the ischaemic tolerance of the viscera and the spinal cord, have not yet been clearly defined. Adverse outcomes due to inappropriate temperature management (core temperatures too high for the required duration of distal arrest) are probably highly underreported. Complications historically associated with hypothermia, namely excessive bleeding, are possibly overestimated. Trading effective neuroprotection and excellent outcomes for the risk of prolonged 'warm' distal ischaemia might constitute a significant step back, jeopardizing visceral and, in particular, spinal cord integrity, with unpredictable consequences for long-term outcome and quality of life, particularly affecting those in need of more complex surgery or with previous neurological deficits.

Continuous cerebral and myocardial perfusion during one-stage repair for aortic coarctation with ventricular septal defect

Controversy still exists concerning the use of deep hypothermic circulatory arrest (DHCA) and selective antegrade cerebral perfusion (SACP) for repair of aortic coarctation (CoA) with ventricular septal defect (VSD). This report therefore describes outcomes of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia compared with DHCA and SACP. Retrospective analysis was performed for 110 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Patients repaired under CCMP with mild hypothermia (32 °C) (group A, n = 60) were compared with those repaired under DHCA (18 °C) and SACP (group B, n = 50). In group A, the single arterial cannula perfusion technique was used for 15 patients (25 %), and the dual arterial cannula perfusion technique was used for 45 patients (75 %). The preoperative data were similar in the two groups. Group A had no hospital mortalities, compared with two mortalities (4 %) in group B. Group A had shorter myocardial ischemic and cardiopulmonary times, fewer delayed sternal closures, a shorter time to extubation, lower postoperative lactate levels, and fewer patients with low cardiac output requiring extracorporeal membrane oxygenation or with multiorgan failure than group B. During the postoperative course, no clinical or electrical neurologic events occurred in either group. The mean follow-up period was 5.2 ± 3.2 years for group A and 7.5 ± 3.1 years for group B (P = 0.048). One late death occurred in group B and no late deaths in group A. The actuarial survival for the two groups was similar (100 % for group A vs 96 % for group B; P = 0.264). The freedom from all types of cardiac reintervention was 96.7 % in group A and 89.6 % in group B (P = 0.688). All the patients were free of neurologic symptoms. The authors' perfusion strategy using CCMP with mild hypothermia for repair of CoA with VSD is feasible, safe, and associated with improved postoperative recovery and should be the method of choice.

Outcome of continuous cerebral and myocardial perfusion under mild hypothermia for aortic coarctation with ventricular septal defect repair

BACKGROUND

Controversy still exists on the use of the optimal cardiopulmonary bypass (CPB) management in aortic coarctation (CoA) with ventricular septal defect (VSD) repair. We report the outcome of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia.

METHOD

This is a retrospective analysis of 60 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Single arterial cannula perfusion technique was used in 15 (25%) patients, and a dual arterial cannula perfusion technique was used in 45 (75%) patients.

RESULTS

There were no hospital or late mortalities. Average CPB time was 105 ± 28 minutes, aortic clamp 27 ± 7 minutes, and descending aortic cross-clamp time 24 ± 5 minutes. Average continuous cerebral perfusion flow was 64 ± 8 mL/kg per minute. No patient needed delayed sternal closure. Average duration of ventilation was 38 ± 20 hours, ICU stay 7 ± 3 days, and hospital stay 14 ± 6 days. No patient required revision for bleeding and/or extracorporeal membrane oxygenation support. No neurologic complications were noted.

CONCLUSION

A perfusion strategy using CCMP with mild hypothermia for CoA and VSD repair is feasible and safe.

Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9±2.6 post circulatory arrest to 3.4±2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3±3.5 mmol/L, intra-operatively, which normalized to 28.4±2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25±0.10, corrected to 7.43±0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361±104 and 253±85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50±35 minutes, respectively. The mean time required for systemic rewarming was 95±66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.

State of the art in neuroprotection during acute type A aortic dissection repair

Temporary (TND) or permanent neurologic dysfunctions (PND) represent the main neurological complications following acute aortic dissection repair. The aim of our experimental and clinical research was the improvement and update of the most common neuroprotective strategies which are in present use.

Hypothermic circulatory arrest (HCA): Cerebral metabolic suppression at the clinically most used temperatures (18-22°C) is less complete than had been assumed previously. If used as a ‘stand-alone’ neuroprotective strategy, cooling to 15-20°C with a jugular SO2 ≥ 95% is needed to provide sufficient metabolic suppression. Regardless of the depth of cooling, the HCA interval should not exceed 25 min. After 40 min of HCA, the incidence of TND and PND increases, after 60 min, the mortality rate increases.

Antegrade selective cerebral perfusion (ASCP): At moderate hypothermia (25-28°C), ASCP should be performed at a pump flow rate of 10ml/kg/min, targeting a cerebral perfusion pressure of 50-60mmHg. Experimental data revealed that these conditions offer an optimal regional blood flow in the cortex (80±27ml/min/100g), the cerebellum (77±32ml/min/100g), the pons (89±5ml/min/100g) and the hippocampus (55±16ml/min/100g) for 25 minutes. If prolonged, does ASCP at 32°C provide the same neuroprotective effect?

Cannulation strategy: Direct axillary artery cannulation ensures the advantage of performing both systemic cooling and ASCP through the same cannula, preventing additional manipulation with the attendant embolic risk. An additional cannulation of the left carotid artery ensures a bi-hemispheric perfusion, with a neurologic outcome of only 6% TND and 1% PND.

Neuromonitoring: Near-infrared spectroscopy and evoked potentials may prove the effectiveness of the neuroprotective strategy used, especially if the trend goes to less radical cooling.

Conclusion: A short interval of HCA (5 min) followed by a more extended period of ASCP (25 min) at moderate hypothermia (28°C), with a pump flow rate of 10ml/kg/min and a cerebral perfusion pressure of 50 mmHg, represents safe conditions for open arch surgery.

Results of Proximal Arch Replacement Using Deep Hypothermia for Circulatory Arrest: Is Moderate Hypothermia Really Justifiable?

The use of selective cerebral perfusion with warmer temperatures during circulatory arrest has been increasingly used for arch replacement over concerns regarding the safety of deep hypothermic circulatory arrest (DHCA). However, little data actually exist on outcomes after arch replacement and DHCA. This study examines modern results with DHCA for proximal arch replacement to provide a benchmark for comparison against outcomes with lesser degrees of hypothermia. Between July 2005 and June 2010, 245 proximal arch replacements (“hemiarch”) were performed using deep hypothermia; mean minimum core and nasopharyngeal temperatures were 18.0 ± 2.1°C and 14.1 ± 1.6°C, respectively. Adjunctive cerebral perfusion was used in all cases. Concomitant ascending aortic replacement was performed in 41 per cent, ascending plus aortic valve replacement in 23 per cent, and aortic root replacement in 32 per cent. Mean age was 58 ± 14 years; 36 per cent procedures were urgent/emergent. Mean duration of DHCA was 20.4 ± 6.2 minutes. Thirty-day/in-hospital mortality was 2.9 per cent. Rates of stroke, renal failure, and respiratory failure were 4.1 per cent (0.8% for elective cases), 1.2 per cent, and 0.4 per cent, respectively. Deep hypothermia with adjunctive cerebral perfusion for circulatory arrest during proximal arch replacement affords excellent neurologic as well as nonneurologic outcomes. Centers using lesser degrees of hypothermia for arch surgery, the safety of which remains unproven, should ensure comparable results.

The impact of deep and moderate body temperatures on end-organ function during hypothermic circulatory arrest

OBJECTIVE

Hypothermic circulatory arrest (HCA) at different temperatures is a protection technique for operations involving the aortic arch. In combination with selective cerebral perfusion, higher arrest temperatures for the remaining body may be permitted. However, the ischaemic/reperfusion injury (I/R) in various organ systems, other than the brain, related to the specific HCA temperature has so far not been evaluated.

METHODS

Fourteen pigs were randomly assigned to 60 min of sole HCA at 20 or 30 °C temperature, weaned from cardiopulmonary bypass (CPB) and followed 4h after HCA. Besides complex haemodynamic monitoring, laser-Doppler spectrophotometry for measuring capillary blood flow, tissue oxygen saturation and post-capillary venous filling pressures of the bowel was installed. At the end of experiment, organs were perfusion fixated and harvested.

RESULTS

During the entire experiment, haemodynamics revealed no differences between the groups. CPB bypass times were 177 ± 12 min in the 20 °C and 158 ± 11 min in the 30 °C group, respectively (p = 0.02). During reperfusion, lactate levels were initially significantly higher in the 30 °C animals (p = 0.001) but subsequently declined. Microcirculatory blood flow and velocity in the bowel were significantly reduced during cooling and reperfusion (p < 0.05), but were independent of final HCA temperature. Histological evaluation revealed significantly more oedema formation in the bowel wall of the 30 °C animals (p = 0.05).

CONCLUSIONS

Higher levels of circulating lactate levels during reperfusion indicate less effective organ protection at 30 than at 20 °C after 60 min of HCA. This is further substantiated by histological evidence for a more pronounced oedema inflammatory response within the bowel wall.

Predictors of massive transfusion with thoracic aortic procedures involving deep hypothermic circulatory arrest

OBJECTIVE

Massive perioperative blood product transfusion may be required with thoracic aortic operations and is associated with poor outcomes. We analyzed independent predictors of massive transfusion in thoracic aortic surgical patients undergoing deep hypothermic circulatory arrest.

METHODS

The study consisted of 168 consecutive patients undergoing open thoracic aortic procedures involving deep hypothermic circulatory arrest between July 2005 and August 2008. We identified 26 preoperative and procedural variables as potentially related to blood product use, tested for association with total blood products transfused by multivariate linear regression model, and constructed logistic regression model for massive transfusion (requiring ≥ 5 units of transfused packed red blood cells between incision and 48 postoperative hours).

RESULTS

Multivariate linear regression determined that 6 significant variables accounted for 42% of variation in total blood products transfused: age (P = .008), preoperative hemoglobin (P = .04), weight (P = .02), cardiopulmonary bypass time (P < .0001), emergency status (P < .0001), and resternotomy (P < .0001). Final predictive logistic regression model included 1-g/dL increase in preoperative hemoglobin (odds ratio, 0.54; 95% confidence interval, 0.43-0.69; P < .0001), 10-minute increase in cardiopulmonary bypass time (odds ratio, 1.15; 95% confidence interval, 1.05-1.26; P = .0026), and emergency status (odds ratio, 4.02; 95% confidence interval, 1.53-10.55; P = .0047.

CONCLUSIONS

Cardiopulmonary bypass time, emergency status, and preoperative hemoglobin were independent predictors of massive transfusion. These variables, along with weight, age, and resternotomy, were associated with total blood product use in thoracic aortic operations involving deep hypothermic circulatory arrest.

Managing fibrinolysis without aprotinin

Cardiopulmonary bypass increases perioperative bleeding and produces a consumptive coagulopathy, which is defined as the simultaneous production of thrombin and fibrinolysis. Thrombin formation and fibrinolysis primarily occur in the surgical wound and peak at the time heparin is reversed by protamine. Neither aprotinin nor lysine analogs successfully control bleeding in many complex procedures, reoperations, aortic resections, or in implantations of mechanical circulatory devices. This analysis reviews the mechanisms involved and current treatment protocols, with the conclusion that changes in treatment protocols rather than use of a specific anti-fibrinolytic drug may provide better control of bleeding in these patients.

Analysis of the risk factors of postoperative respiratory dysfunction of type A aortic dissection and lung protection

AIM

Retrospectively to analyze the risk factors of postoperative respiratory dysfunction (RD) in 196 patients with type A dissection operated on with cerebral perfusion and a lower body hypothermia circulatory arrest (HCA) and to investigate the method of the lung protection.

METHODS

From January 2005 to April 2008, 196 patients with type A dissection underwent surgical repair with cerebral perfusion and HCA. There were 142 male patients and 54 female patients, with ages from 17 to 78 years. Antegrade selective cerebral perfusion (SCP) through the axillary artery was performed for 168 patients and retrograde cerebral perfusion (RCP) from the superior vena cava for 28 patients. All the factors underwent univariate and multivariate analysis.

RESULTS

Mean cardiopulmonary bypass (CPB) duration was (186+/-56) minutes and mean cerebral perfusion time was (35+/-15) minutes; mean HCA time was (39+/-14) minutes. Postoperative RD was detected in 26 patients (13.3%). Multivariate analysis showed that the longer duration of circulatory arrest (CA), P=0.008, OR=1.048, and the higher temperature in the bladder during CA, P=0.002, OR=1.614, were independent risk factors of postoperative RD. There was a higher mortality (23.1%, P=0.025) in patients with postoperative RD when compared with the other patients.

CONCLUSION

The longer duration of CA and the higher temperature in the bladder during CA were found to be the independent risk factors of postoperative RD after type A aortic dissection surgery. Attention should be paid to lung protection for these patients and the adjunct of continuing descending aortic perfusion and cerebral perfusion should be a safe and feasible procedure and it would be valuable to perform a prospective trial.

Total arch replacement with stented elephant trunk technique: a proposed treatment for complicated Stanford type B aortic dissection

OBJECTIVES

The treatment of Stanford type B aortic dissections involving the arch or associated with proximal aortic aneurysms remains a surgical challenge. We report our results with total arch replacement with the stented elephant trunk (SET) procedure for these complicated Stanford type B aortic dissections.

METHODS

Between December 2003 and June 2008, 31 patients were admitted for complicated type B dissection (12 acute, 19 chronic). The mean age at operation was 44.3 +/- 10.6 years (range: 22-68 years). The surgeries were performed by using total arch replacement combined with SET implantation. Enhanced computed tomography (CT) was performed before discharge as well as 3 months and annually to evaluate the condition of the graft and the residual false lumen.

RESULTS

The procedure was successful in all but two patients; two patients died of multiple organ failure following surgery. No paraplegia was observed after surgery. Follow-up was completed in 27 of 29 patients and the mean follow-up period was 18.4 +/- 12.3 months (range: 6-54 months). During follow-up CT scans, thrombus formation was observed in the descending aortic false lumen excluded by the stented graft in most patients. One patient died during follow-up while two patients with Marfan syndrome underwent successful operations for replacement of the remaining descending and abdominal aorta.

CONCLUSION

Total arch replacement with the SET procedure has emerged as a viable option for complicated type B dissections and is associated with low morbidity and mortality. At mid-term follow-up, most patients have either thrombosed or have had no further increase in the false lumen of the descending aorta.

Risk factors for prolonged mechanical ventilation following surgery for acute type a aortic dissection

BACKGROUND

The aim of this study was to identify predictors of prolonged mechanical ventilation (PMV) following surgery for acute type A aortic dissection (AAAD) and to assess the influence of this complication on clinical outcomes.

METHODS AND RESULTS

A total of 243 patients underwent emergency surgery for AAAD in the period of 1997-2006. Ten patients died within 48 h after surgery. The remaining 233 patients were divided into 2 groups according to the duration of mechanical ventilation; less than 48 h (group A: n=149) or 48 h or longer (group B; n=84). Multivariate analysis was used to identify predictors of PMV. Short and late outcomes were compared between groups. Multivariate analysis showed that shock (systolic BP <90 mmHg; p=0.007), postoperative renal dysfunction (creatinine >2.0 mg/dl; p=0.016), coronary artery bypass grafting (CABG) (p=0.017), and limb ischemia (p=0.044) were independent predictors of PMV. There was no significant difference in in-hospital mortality (group A, 2.7% vs group B, 3.6%) or 5-year survival (group A, 85.9% vs group B, 76.8%).

CONCLUSIONS

Shock, limb ischemia, CABG, and postoperative renal dysfunction increase the risk for PMV. Knowing the predictors of PMV should help optimize postoperative management of these patients.

Hypothermie in der Herzchirurgie

Since the beginning of the era of cardiac surgery hypothermia remains a mainstay in perioperative management. This role is increasingly being questioned because of many disadvantages and the lack of evidence of advantages. Using modern techniques of perfusion and myocardial protection as well as improved surgical techniques the results with normothermia seem to be comparable. The importance of hypothermia in present day cardiac surgery is discussed with respect to myocardial and cerebral protection.

The safety of moderate hypothermic lower body circulatory arrest with selective cerebral perfusion: A propensity score analysis

OBJECTIVE

There is no common guideline on what temperature should be achieved at the lower body circulatory arrest followed by the initiation of selective cerebral perfusion.

METHODS

Between October 1999 and August 2005, a total of 377 patients underwent repair of the aortic arch with selective cerebral perfusion and hypothermic circulatory arrest at 20 degrees C to 28 degrees C and were divided into two groups: (1) 125 patients with deep lower body circulatory arrest at 20 degrees C to 24.9 degrees C (deep lower body circulatory arrest group) and (2) 252 patients with moderate lower body circulatory arrest at 25 degrees C to 28 degrees C (moderate lower body circulatory arrest group). To compensate for the differences in patient characteristics, we used a propensity score matching analysis, and comparable patients, 92 patients from each group, were identified for final analysis.

RESULTS

There were no significant differences in mortality or morbidity between deep and moderate lower body circulatory arrest, in either the entire study cohort or the propensity-matched cohort. C-reactive protein level 1 day after the operation approached but fell short of significance (108.4 +/- 47.7 mg/L in deep lower body circulatory arrest group and 95.8 +/- 44.2 mg/L in moderate lower body circulatory arrest group, P = .07). The mean temperatures at the initiation of lower body circulatory arrest were 24.1 degrees C +/- 2.2 degrees C in patients who underwent reexploration for bleeding and 24.9 degrees C +/- 1.8 degrees C in patients who did not (P = .025); the difference also reached statistical significance in multivariate analysis (P = .046, odds ratio 0.796).

CONCLUSIONS

Our results suggest that moderate lower body circulatory arrest can be safely performed for aortic arch repair. In fact, postoperative inflammatory response tended to be lower in patients with moderate lower body circulatory arrest than those with deep lower body circulatory arrest, and deep lower body circulatory arrest was a strong risk factor for reexploration for bleeding.

Aortic Arch Surgery: Thoracoabdominal Perfusion During Antegrade Cerebral Perfusion May Reduce Postoperative Morbidity

BACKGROUND

This study aimed to assess the results of the introduction of thoracoabdominal perfusion (TAP) in the surgical strategy for aortic arch replacement with cerebral protection.

METHODS

Two hundred two arch procedures performed with moderate hypothermia (22 degrees to 26 degrees C) and antegrade cerebral perfusion (ACP) were the objects of retrospective investigation. Acute type A dissection was the indication in 164 patients, aortic aneurysm in 38. In 80 patients, during ACP, the thoracoabdominal aorta was perfused either in an antegrade fashion through proximal descending aorta endoluminal cannulation (in 62 dissections), or retrograde through femoral artery cannulation with proximal descending aorta endoluminal occlusion (in 18 aneurysms). Hospital mortality and morbidity rates were compared between the two treatments (group A: ACP only, 122 patients; group B: ACP plus TAP, 80 patients) and the underlying aortic disease (dissection/aneurysm) was stratified.

RESULTS

Cerebral perfusion (p = 0.008) and cardiopulmonary bypass times (p = 0.035) were significantly longer in group B. No complication related to the TAP technique was observed in group B. Overall hospital mortality was 12.9%, without significant difference between groups. No differences were found in terms of permanent neurological dysfunction between groups A (9.3%) and B (9.1%; p = 0.58). Group B patients showed lower rates of respiratory failure (18.2% versus 30.5% in group A; p = 0.038), shorter mechanical ventilation times (18.1 +/- 26 hours versus 57.9 +/- 70.1; p < 0.001) and lower incidence of acute renal failure (6.5% versus 18.6%; p = 0.012). Shorter intensive care and hospital stays were observed in group B (p = 0.02).

CONCLUSIONS

The adjunction of TAP to ACP was associated with lower rates of end-organ complications, even in more extensive and time-consuming procedures.